Contamination, adulteration and food quality

Contamination: harmful or unwanted foreign substances (chemicals, microbes, diluents) in food, before, during or after processing or storage.

Adulteration: lowering the quality of food, by adding cheaper material or removing a valuable part. It also includes contamination while food is grown, stored, processed and transported. The substances that make food unsafe are called adulterants.

Food quality is everything that affects a food's value to the buyer:

• Negative sides: spoilage, contamination, adulteration, hazards.
• Positive sides: colour, flavour, texture, nutrition and other sensory properties, and social factors.

Safety comes first. Food services must follow good manufacturing practices: good raw materials and water; clean premises, people and equipment; the right storage temperatures; food hygiene; and good service.

Some simple tests for adulterants:

• Iodine turns starch blue, so it shows starch added to milk.
• Concentrated HCl turns metanil yellow (a banned dye) in turmeric pink.
• A sugar-HCl test shows vanaspati in ghee, through the sesame oil that vanaspati contains.

Safe first, then good.